On Tuesday, Musk publicly apologized to Haraldur Thorleifsson, an Icelandic entrepreneur who joined Twitter in 2021 when the social media company bought his design firm. He was fired during the company’s most recent layoffs a few weeks ago.

Musk’s apology came after a series of back and forth posts Monday and Tuesday in which Thorleifsson asked for clarity on his employment status while Musk repeatedly quizzed him on his role at the company. The conversation took a turn for the worse when Musk concluded that Thorleifsson “did no actual work” at Twitter and that he had used an excuse that “he had a disability that prevented him from typing.”

Thorleifsson, who worked as a middle manager in Twitter’s design team in a role that rarely required typing, explained in a follow-up post that he had muscular dystrophy, a degenerative disease affecting his muscles that has left him confined to a wheelchair for the past 20 years.

While Musk’s behavior was shocking, it wasn’t technically illegal or a violation of the Americans with Disabilities Act, disability law experts tell Fortune. But it shows how bad bosses have wide latitude in the workplace, especially when it comes to how they treat vulnerable employees.

Thorleifsson did not immediately respond to Fortune’s request for comment. Twitter, which has eliminated most of its PR department, also didn’t respond.

Fear of the ‘disability con’

Musk’s online comments about Thorleifsson were an unpleasant way to interact with an employee—current or former. But technically, the Twitter CEO didn’t break any laws, legal experts said.

“It was very rude, but it’s not illegal,” Doron Dorfman, a professor at Seton Hall University who focuses on disability and employee discrimination law, told Fortune. Because Thorleifsson was the one who disclosed the specifics of his disability, and unless he has proof Twitter fired him for his disability, Musk’s offensive comments likely aren’t grounds for a successful lawsuit, Dorfman said.

But the scenario speaks to a bigger workplace issue that usually flies under the radar and doesn’t get much attention online. Musk’s comments about Thorleifsson represent what Dorfman calls “fear of the disability con,” or suspicion that employees with access to special accommodations are taking advantage of the hand that feeds them.

“This is a great example of it because Musk really kind of used all the tropes about employees with a disability,” Dorfman said, adding that an employer accusing an employee of lying their way out of work because of a disability is common for vulnerable workers.

The share of Americans with disabilities participating in the workforce has increased over the past decade, from 17.8% in 2012 to 21.3% in 2022, according to the Bureau of Labor Statistics. Remote work during the COVID-19 pandemic supercharged that trend as working from home allowed those with physical disabilities and immunodeficiencies to join the workforce in greater numbers than ever. Hiring people with disabilities, whether remotely or in-person, might also be a savvy business choice, as a 2018 Accenture study found that companies with policies geared towards hiring more employees with disabilities and who double down on making workplaces accessible are more likely to have higher profit margins and revenue.

But even as more Americans with disabilities have piled into the workforce, many have also become vulnerable to bullying and condescension. Dorfman found in a 2019 paper that around 60% of Americans with disabilities said that others question the legitimacy of their condition and whether they actually require accommodations. This applies both to those with visible disabilities, such as Thorleifsson, as well as invisible ones, which include those with immune deficiency diseases.

“People aren’t really saying this stuff on Twitter, but disabled employees can be made to feel like their requests are ridiculous,” Katherine MacFarlane, a lawyer and law professor in Baton Rouge who specializes in anti-discrimination law, told Fortune. “There’s an abundance of microaggressions and just flat-out refusals to make accommodations, but I’ve heard the kind of stuff Elon said, said in various different ways throughout my life.”

Elon Musk’s bad boss rep

Two things make Musk’s interaction with Thorleifsson stand out from the many similar situations vulnerable employees go through daily in the workplace. First, the encounter was highly public, with Musk’s tweet that linked Thorleifsson’s work ethic to his disability garnering over 110,000 likes and over 6,000 retweets. Second, and more concerningly for Musk, it isn’t the only incident in which the Twitter CEO has publicly mocked his own employees.

Even before taking over Twitter, Musk was well-known for his demanding leadership style at Tesla and SpaceX, both of which he currently runs as CEO. But in the year since acquiring Twitter, he has taken the concept of a temperamental boss to a new level.

In April, soon after proposing his $44 billion acquisition of Twitter, Musk went online to attack the company’s then-executives. In November, Musk also publicly feuded with a Twitter employee online and then announced the worker’s dismissal. Last month, Musk also reportedly fired an employee who said the reason Musk’s Twitter account was getting fewer reactions from users was that people weren’t as interested in him anymore.

As for Thorleifsson, he wasn’t even the first employee who Musk attacked in terms of a disability. In November, after a few dozen Twitter workers were reportedly fired for criticizing Musk, he sarcastically said that one of them had a “tragic case of adult onset Tourette’s.”  

Experts say that Musk’s frequent use of the social media platform to berate employees can be harmful, especially if he resorts to tropes to do so.

“Seeing such a powerful person put those thoughts out there on such an accessible platform, it really represents so much that people with disabilities deal with in the workplace,” MacFarlane said. “He was running through every stereotype: ‘You don’t need the money. You get it from somewhere else. You’re faking your disability. Do you even do any work?’”

In his public apology to Thorleifsson Tuesday, Musk said the former employee was considering remaining at Twitter. While no one can say why Musk uncharacteristically decided to apologize, legal considerations may have played a role.

“If the employee decides eventually to sue for disability discrimination, Musk’s comments could be very strong direct evidence to bias against people with disabilities at Twitter. I believe that in order to be safe, Musk took a step back after possibly discussing it with his legal team. It’s really about taking precautions,” Seton Hall’s Dorfman said.

Employers apologizing after berating an employee for a disability is uncommon, experts say, but that is largely because these situations rarely if ever get as much exposure as an online conversation with Musk does.

“There’s been an uproar over it, but it’s easy to get mad at Elon. It’s harder to make day-to-day changes and to support the individuals with disabilities in your everyday life,” Macfarlane said.